engine performance help

[bob58o]

whats the best way to get springs compressed? American ingenuity?
my friend has 22s and he said thos are really hard so that's what im worried about with 26 lb springs.

Well if you have the older style non-hemi Head, or are going to use a Honda head, and plan on using the stock valves... the retainers just slip onto the valve. I was able to fairly easily compress the spring and slip on the retainer using my thumbs with 26 lb springs.

I just used something inside the chamber to support the face of the valve. I think I used my knee, a rolled up towel,... anything to keep the valve from dropping out. It’s much tougher when you have SS valves with split style keepers. Those are the types of keepers/retainers that come on the newer non-Hemis. For those, with 26+ lb springs I made a tool using a C clamp, and rigid conduit coupler, and a washer.

6” harbor freight C clamp
1/2” rigid conduit coupler (1.75” long)
1/2” washer

BTW, if you’re planning on using a Honda head, it comes with the smaller 25/24mm valves. If you want more HP, I’d look into at least a 27/25mm Head. I can’t find it now, but NR had some nice heads on sale for $120 bucks. Came milled and ported with 27/25mm valves.

 

[bob58o]

Seems like this head is milled, ported, has had a valve job and comes with 27/25mm valves.
https://rover.ebay.com/rover/0/0/0?mpre=https://www.ebay.com/ulk/itm/132919764118

---------- Post added at 09:20 PM ---------- Previous post was at 09:18 PM ----------

This one has been ported and comes with champion rockers and SS valves.
https://rover.ebay.com/rover/0/0/0?mpre=https://www.ebay.com/ulk/itm/312430154035

 

[tgus3]

Thanks you guys have been a lot of help

---------- Post added at 09:48 PM ---------- Previous post was at 09:24 PM ----------

So I ordered that second head that's not milled, my dad has a machine shop so it wont be that hard to do it myself

I noticed the honda and predator pushrods are different lengths. Does it matter what size I order my chromoly ones?

 

[bob58o]

Not sure what size you need. I’ve never used those rocker arms.
It also matters how much you mill the head. Your best bet might be to purchase the cut to length ones. Mill the head to get the desired compression ratio, then test with the stock pushrods. If they are too long, grind the stock pushrods down. Little by little. Once you find the length of the pushrods that gives you the proper geometry, then cut the “cut to length” ones to match.

I don’t have the time to watch this, but Jody probably has great information in this video that will be very helpful.
https://youtu.be/ki87LOkks48

P.S. It also matters if the camshaft has a larger or smaller base circle.
So when testing the pushrod length, make sure you have the camshaft you will be using installed. And also the head gasket you want to use.

---------- Post added at 10:58 PM ---------- Previous post was at 10:42 PM ----------

That head seems like a decent deal. The stud kit is $15-$20 IIRC. The SS valves are like $15 each. The champion rockers are around $25. So you get a ported head for like $20.
You’ll have to see what is included, but you may need to purchase the retainers and keepers for those valves.
http://www.nrracing.com/product-p/smret-200-alum.htm
http://www.nrracing.com/product-p/132-10ka0-31.htm

 

[tgus3]

well the head hasn't arrived yet but if its the normal 60thou on it im planning to take .050 off.

How do you tell if the rods are long or short? will it still turn over if there long or will it feel loose if there short or what...

 

[bob58o]

I’ve always used lash caps. If the pushrods are the correct length the marks the rocker arms leave on the lash caps will be centered on the lash caps.

 

[Flyinhillbilly]

I’ve always used lash caps. If the pushrods are the correct length the marks the rocker arms leave on the lash caps will be centered on the lash caps.

Lash caps are good to use with a pair of exhaust retainers because they help lock the retainer on the valve.
When finding your valvetrain geometry (pushrod length) you need to color the lash caps with a sharpie and spin the engine. You’re looking for the length that gives you the smallest mark on the cap possible. Improper valve train geometry robs power and wears out the valve guides faster since it pulls sideways on the valve as it cycles.

 

[tgus3]

So I got my head in a few days ago, and it looks like I cant mill the head because its already to low. Is there different styles of predator heads or what?

Also this is what I found when I opened my block.

 

[tgus3]

I think I can still mill it 10 or 20thou but idk...

that one piece is the oil dipper.

 

[65ShelbyClone]

The head looks like it was already milled.

 

[ezcome-ezgo]

Poor thing.

 

[tgus3]

Yeah, I talked to the guy again and he said its not milled its a new head but I've never seen stock ones like this...

 

[65ShelbyClone]

Do you have calipers? Measuring from the valve cover rail to the head gasket surface ought to show whether that's true or not. Stock kart classes check it as a tech item, so the specs are out there.

Don't trust anything a previous owner says until you can verify it. Usually what they they tell you are assumptions and lies. They cover the lies by presenting them as an assumption.

 

[tgus3]

Ive looked a bit for the measurements and cant find them. Im just gonna measure one of my friends stock heads and compare them.

 

[tgus3]

also a couple more questions, you can see my spark plug in the pic,is it sticking out to far?

And I guess there a reason everyone on youtube uses clear valve covers with champion rockers cause they stick out farther than stock.

 

[65ShelbyClone]

also a couple more questions, you can see my spark plug in the pic,is it sticking out to far?

If it's less than about 0.040" from the piston, then yes.

 

[bob58o]

That head surely looks milled to me. They make washers to pull the spark plug out of the chamber.
Let’s see pics of the rest of the carnage. Is that the oil dipper from the connecting rod?
EDIT: I missed that line.

---------- Post added at 11:32 PM ---------- Previous post was at 11:01 PM ----------

I'd stay away from the clear cover. Many say they don't stay sealed up.
http://www.nrracing.com/product-p/200vcspacer.htm

CC the head if you can, but I purchased a burette and a 1/2" thick Lexan 5"x5" plate to do it accurately.

 

[tgus3]

The ad says its a new head. And when I emailed him he said same but that he has rtc-8 head that has the normal ridge on it. The ad says this head is a jt-172. So I guess there's a diff in stock ones?

Im Stil waiting to measure a stock one so ill get back with the specs in a few days.

 

[tgus3]

So I measured a stock head and my new one and yes theres a difference.

Stock predator 212-about 2.91in

the supposedly stock jt172 head-about 2.85in

This is measuring from the rail where the valve cover goes to the opposite side where the gasket goes.
So there is a .060 diff so I guess im gonna treat it like its milled.

 

[65ShelbyClone]

I have an unmodified 196 clone replacement head that also measures 2.910".

The fact that yours is exactly 0.060" shorter indicates that it has been milled. That is a common amount to take off.